Hello there
thank you for your offer but I believe I still don't have the qualifications to be a manga artist, I do love drawing manga and I already have made many stories which I draw on my notebook, but as you can see I'm still 15 and my studies are in its crucial stage because I will be a 4th year high school student this year and I need to focus in my studies in order to graduate
But I really appreciate your offer, I hope that someday when I finish studying in school I will be able to join your company in publishing mangas that will surely be loved by manga lovers
I hope that you will be able to find manga artists that accepts your invitation! Good Luck!